While changes in mRNA decay rates account for approximately 50% of the regulation of gene expression in the cell, an assay to accurately and reliably measure mRNA half lives is currently not available. In particular, the deficiency of reliable commercial kits which enable the average biomedical research lab to effectively investigate mRNA decay rates is significantly slowing down progress in this area. In order to meet this need, we have developed a novel approach involving the direct PCR analysis of metabolically labeled RNA molecules to determine mRNA decay rates. In this application, we propose to demonstrate feasibility of this novel approach and validate its effectiveness in two aims. First, we will optimize a unique nucleoside analog metabolic labeling technique which utilizes a simple and historically validated conjugation chemistry approach coupled with selective RT-PCR amplification of the desired mRNA population. Second, we will validate our metabolic labeling technique/RT-PCR approach using synthetic mRNAs and several well-characterized endogenous cellular mRNAs. Collectively this kit will enable a non-biased, user-friendly, reliable method for the routine determination of mRNA half lives and the study of regulated RNA degradation. PUBLIC HEALTH RELEVANCE: Current methodology to study the degradation rates of RNAs in a cell contains procedural bias and is not reliable. While homebrew methods are available they often waste lab personnel time performing assay optimization and validation. Given the fact that changes in mRNA decay rates are likely responsible for almost half of the regulation of gene expression in a cell the lack of a reliable technology to accurately assess mRNA degradation rates is hampering many efforts. We thus propose a novel method to address these issues.